Reverse rotation detection in rotating machinery

ABSTRACT

A system includes a sensor configured to monitor rotating machinery and generate a signal based on a physical characteristic of the rotating machinery. The system also includes a monitoring system with a processor. The processor of the monitoring system is configured to receive the signal from the sensor. The processor determines an occurrence of reverse rotation of the rotating machinery by comparing the signal to a normal operating pattern to generate an initial value. The processor generates a notification signal indicating the occurrence of a reverse rotation.

CROSS REFERENCE TO RELATED APPLICATIONS

This application is a continuation of U.S. patent application Ser. No.14/483,977 filed Sep. 11, 2014, entitled “REVERSE ROTATION DETECTION INROTATING MACHINERY,” which is hereby incorporated herein by reference inits entirety.

BACKGROUND

The invention relates generally to monitoring systems, and, moreparticularly, to an automated system for detecting reverse rotation onan industrial system using turbo machinery.

Generally, turbo machines, such as turbines, compressors and pumps, aredesigned to transfer energy between a rotor and a fluid. While turbinestransfer energy from a fluid to a rotor, compressors and pumps transferenergy from a rotor to a fluid. Many turbo machines are designed forprocessing such fluids in a unique direction (clockwise orcounterclockwise). As such, the machines are not designed to withstandrotation opposite the designed direction. However, operation processparameters or malfunctioning valves can result in backward pressureoccurring. This backward pressure can cause turbo machines to rotate inthe reverse direction of a machine's design. As a result, the drivenpiece of equipment can become the driver. Reverse rotation can affectthe integrity of the machine ultimately causing stress and/or damage, ifleft unchecked. For instance, extreme torque in the reverse directioncan cause coupling and rotor problems. Additionally, reverse rotationcan damage bearings, seals, and other components that may only bedesigned to operate in the forward direction.

Presently, many problems may be encountered in trying to monitor rotorreverse rotation events in turbo machinery. Under certain conditions,the machine may rotate in the reverse direction unnoticed. For instance,incorrect operation of downstream discharge, shutoff, and check valvesduring shutdown events often goes unnoticed. Moreover, reverse rotationmay also not be limited to just one machine, but can be a widespreadissue with sister machines of similar applications at a plant.Accordingly, there is a need for a monitoring system for reverserotation of the rotor in turbo machinery.

BRIEF DESCRIPTION

Certain embodiments commensurate in scope with the originally claimedinvention are summarized below. These embodiments are not intended tolimit the scope of the claimed invention, but rather these embodimentsare intended only to provide a brief summary of possible forms of theinvention. Indeed, the invention may encompass a variety of forms thatmay be similar to or different from the embodiments set forth below.

In one embodiment, a device includes a communication interfaceconfigured to receive a signal related to a rotational speed, avibration, or any combination thereof of a rotating machine element, amemory for storing an operating pattern of the rotating machine element,wherein the operating pattern is related to the received signal, and aprocessor coupled to the communication interface and the memory, whereinthe processor is configured to determine an occurrence of reverserotation of the rotating machine element by comparing the signalreceived from the communication interface to the operating patternstored in the memory, and generate an initial value indicative of theoccurrence of the reverse rotation of the rotating machine element.

In a second embodiment, a system includes a sensor configured to monitorrotating machinery and generate a signal based on a physicalcharacteristic of the rotating machinery, and a monitoring systemcomprising a processor configured to receive the signal of the rotatingmachine element, determine an occurrence of reverse rotation of therotating machinery by comparing the signal to an operating pattern togenerate an initial value; and generate a notification signal indicatingthe occurrence of a reverse rotation.

In a third embodiment, a non-transitory computer-readable medium havingcomputer executable code stored thereon, the code comprisinginstructions to receive a signal from a sensor associated with rotatingmachinery, determine an occurrence of reverse rotation of the rotatingmachinery based on the signal and an operating pattern of the rotatingmachinery, and generate a notification signal indicating the occurrenceof reverse rotation of the rotating machinery.

DRAWINGS

These and other features, aspects, and advantages of the presentinvention will become better understood when the following detaileddescription is read with reference to the accompanying drawings in whichlike characters represent like parts throughout the drawings, wherein:

FIG. 1 is a schematic flow diagram of an exemplary steam turbine systemin accordance with the present techniques;

FIG. 2A is a graph illustrating an embodiment of the data received bythe monitor system of FIG. 1 during a normal shutdown operation;

FIG. 2B is a graph illustrating an embodiment of the data received bythe monitor system of FIG. 1 during a reverse rotation event;

FIG. 2C is a graph illustrating an embodiment of the data received bythe monitor system of FIG. 1 during a reverse rotation event;

FIG. 3A is a plot illustrating an embodiment of the data received by themonitoring system of FIG. 1 during normal operation of a rotor meant torotate in counterclockwise direction (viewed from driver to drivenequipment);

FIG. 3B is a plot illustrating an embodiment of the data received by themonitoring system of FIG. 1 during reverse rotation for the same rotorthat is meant to rotate in counter clockwise direction; and

FIG. 4 is a flow diagram of an exemplary method in accordance with thepresent techniques.

DETAILED DESCRIPTION

One or more specific embodiments of the present subject matter will bedescribed below. In an effort to provide a concise description of theseembodiments, all features of an actual implementation may not bedescribed in the specification. It should be appreciated that in thedevelopment of any such actual implementation, as in any engineering ordesign project, numerous implementation-specific decisions must be madeto achieve the developers' specific goals, such as compliance withsystem-related and business-related constraints, which may vary from oneimplementation to another. Moreover, it should be appreciated that sucha development effort might be complex and time consuming, but wouldnevertheless be a routine undertaking of design, fabrication, andmanufacture for those of ordinary skill having the benefit of thisdisclosure.

When introducing elements of various embodiments of the present subjectmatter, the articles “a,” “an,” “the,” and “said” are intended to meanthat there are one or more of the elements. The terms “comprising,”“including,” and “having” are intended to be inclusive and mean thatthere may be additional elements other than the listed elements. Anyexamples of operating parameters and/or environmental conditions are notexclusive of other parameters/conditions of the disclosed embodiments.

With the foregoing in mind, FIG. 1 illustrates an exemplary system formonitoring reverse rotation of a steam turbine system 100. As will beappreciated, the steam turbine system 100 is merely an example, and thepresent embodiments may be used in any type of pump, compressor,turbine, or similar structure which may benefit from a reverse rotationmonitoring system. More specifically, the distinguishing feature of thepresent embodiment is the fact that a driven piece of equipment becomesthe driver. In the steam turbine system 100, a steam turbine 102transfers thermal energy from pressurized steam into mechanical energy.A boiler 104 heats up feed water 108 by combusting fuel 106 to producesteam 110. The highly pressurized steam 110 rotates a rotor 112, losingpressure in the process. The rotor 112 is operatively coupled to a shaft114, such that when the rotor 112 turns, it turns the shaft 114. Theshaft 114 then turns to deliver energy to a load 116. In this manner,one or both of the rotor 112 and the shaft 114 are examples of rotatingmachine elements and/or rotating machinery of the turbine system 100.The lower pressure steam may be reheated, put through an intermediate orlow pressure turbine, or may be output as exhaust 118 to be used withother downstream industrial processes.

The shaft 114 is equipped with sensors (e.g., probes) 120. Oneembodiment may comprise two sensors: a first sensor 120 placed along theshaft 114 at ninety degrees apart from a second sensor 120. As reflectedin the three dimensional coordinate system 124, the first sensor 120 maybe placed on the Y axis of the shaft 114 (e.g. along a top most portionof the shaft 114), and the second sensor 120 may be placed on the X axisof the shaft 114 (e.g. along a side portion of the shaft 114). Thus, thesecond sensor 120 is mounted 90 degrees clockwise from the first sensor120. However, any variety of positioning for any variety of number ofsensors may be used to best provide data about the steam turbine 102, orsimilar turbo machinery. In some embodiments, a notch may be drilled inthe shaft 114 to track each revolution of the shaft 114. The sensors 120transmit signals to a monitoring system 126 using any suitablecommunication method (e.g. hard wired or wireless communication).

In certain embodiments, the sensors 120 may be any of various sensorsuseful in providing various operational data to the reverse rotationmonitoring system 126 including, for example, speed and vibration data.This data may be used not just for reverse rotation detection, but maybe used for a wide variety of purposes. The monitoring system 126 may becomprised of a processor 128 or multiple processors, memory 130, and acommunication interface 132. The processor 128 may be operativelycoupled to the memory 130 to execute instructions for carrying out thepresently disclosed techniques. These instructions may be encoded inprograms or code stored in a tangible non-transitory computer-readablemedium, such as the memory 130 and/or other storage. The processor 128may be a general purpose processor, system-on-chip (SoC) device, orapplication-specific integrated circuit, or some other processorconfiguration.

Memory 130, in the embodiment, includes a computer readable medium, suchas, without limitation, a hard disk drive, a solid state drive, adiskette, a flash drive, a compact disc, a digital video disc, randomaccess memory (RAM), and/or any suitable storage device that enablesprocessor 128 to store, retrieve, and/or execute instructions and/ordata. Memory 130 may include one or more local and/or remote storagedevices.

The monitoring system 126 may have a wide variety of inputs and outputsin the communication interface 132. The communication interface 132 mayinclude, without limitation, a network interface controller (NIC), anetwork adapter, a transceiver, and/or any suitable communication devicethat enables the monitoring system 126 to operate as described herein.The communication interface 132 may connect to a network, to a remotecomputer system (neither shown), or a database using any suitablecommunication protocol, such as, for example, a wired Ethernet protocolor a wireless Ethernet protocol. The communication interface 132 mayreceive signals indicating that the turbine 112 is shutting down,turning on, speeding up, or slowing down. The communication interface132 may receive signals from the sensors regarding, for example, speedand vibration data. The monitoring system 126 may also include aninternal display 134 for displaying data received by the communicationinterface 132 or any analysis performed by the processor 128. Theinternal display 134 may display plots, graphs or charts similar tothose described in FIG. 2A-C or FIG. 3A-B. Alternatively, theinformation could be sent to an external display, locally or remotely,to display similar information.

In certain embodiments, the monitoring system 126 may be programmed orconfigurable (e.g., performed via the processor 128 and the memory 130)to support comparisons of speed and vibration data to normal operatingpatterns. The monitoring system may receive speed and vibration signalsfrom the sensors 120. In one embodiment, the monitoring system 126 isconfigured to receive an indication that the turbine 112 is shuttingdown. This indication may be received from the sensors 120, from aserver, from the steam turbine system 100, or by some other means.Alternatively, the monitoring system 126 may determine that the steamturbine 102 is shutting down based on speed and vibration data of theshaft 114 received from the sensors 120. The monitoring system 126 thendetermines whether a reverse rotation event will occur, is in theprocess of occurring, or has already occurred by comparing data receivedfrom the sensors 120 to normal operating patterns. The monitoring system126 may compare the received data to normal operating patternsinternally with signal processing. As discussed below, the comparisonsof received data against normal operating patterns may include weights(e.g., weighting factors) assigned to different aspects of the speed andvibration data provided by the sensors 120. The normal operatingpatterns may be predetermined according to the steam turbine system 100,user-adjustable, or based on prior shutdown data. Similarly, presetweights may be based on predetermined values, user-adjustable, or basedon prior shutdown data. The preset weights and/or normal operatingpatterns may be stored in the memory 130 or be in hardware of themonitoring system 126. The comparison steps or processes may, forexample, be written in code and stored in the memory 130 to be executedby the processor 128 using, for instance, signal processing.

In certain embodiments, the monitoring system 126 may provideindications of whether or not a reverse rotation has occurred based on,for example, comparing the received values from sensors 120 to normaloperating patterns. Specifically, the monitoring system 126 may beprogrammed or conditioned to generate a signal 136, or a number ofsignals, when one or more comparisons suggest that a reverse rotationevent has occurred. The signal 136 may be sent to a workstation thatincludes a display to show the data in charts, plots, graphs, tables, orsimilar structure. Alternatively, the signal 136 may be sent as an alertof a reverse rotation event to a workstation, a remote server, or adatabase. In addition to the alert signal 136 being sent, dataindicative of the alarm can also be sent to the workstation, remoteserver, or database as further evidence that reverse rotation occurred.As will be appreciated, an alert and data related thereto are merelyexamples of signals sent by the monitoring system 126 and the signal 136sent could be any indication that a reverse rotation event has occurred.Additionally and/or alternatively the signals may be sent to an internaldisplay 134 to display alerts or show the data as charts, plots, graphstables, or similar structure. The data may be shown in a variety offorms to convey evidence that a reverse rotation has occurred. Forinstance, speed trend plots, orbit plots, or waterfall plots may be usedto describe the reverse rotation event.

FIG. 2A-2C are speed trend plots 202 and FIG. 3A-3B are orbit plots 300representative of data that may be received by the monitoring system 126during a shutdown procedure of the steam turbine system 100. Asgenerally discussed above, the monitoring system 126 may generatesignals 136 to output data represented by graphs FIG. 2A, 2B, 2C, 3A, or3B to a workstation or a generated report as further evidence of areverse rotation. Alternatively, the monitoring system 126 may analyze(e.g., using signal processing) the data internally, as is usuallyrepresented in FIG. 2A, 2B, 2C, 3A, or 3B, to determine if a reverserotation will occur, is in the process of occurring, or has alreadyoccurred. Then, the processor 128 may generate a signal 136 indicatingthat a reverse rotation will occur, is in the process of occurring, orhas already occurred.

The speed trend plots of FIGS. 2A, 2B, and 2C show RPM versus time. TheRPM may be as low as 10-30 RPM, or it may be several thousand RPM. Manymachines are designed to only withstand a certain operational RPM. Thesensors 120 may be designed to only monitor the RPM, not the direction,of the shaft.

FIG. 2A is a speed trend plot 202 representative of a typical shutdownoperation (e.g., normal operating pattern) of the steam turbine system100. The time until a rotor 112 or the steam turbine 102 stops moving isknown as the coast down time. In a typical shutdown, the coast down timemay take several minutes (e.g., up to 30 minutes). As the steam turbinesystem 100 shuts down, the sensors 120 relay gradually slower speedsignals to the monitoring system 126 that reflects the coast down inexponential decay line 204.

FIG. 2B is a speed trend plot 202 representative of data during areverse rotation event self-contained after a period of time. Such anevent may occur, for instance, where the steam turbine system 100 isoperating normally except, for example, an improperly timeddischarge/shut-off valve. The discharge/shut-off valve may be locateddownstream of the rotor 112 where steam is given off as exhaust 118. Asillustrated in the speed plot 202 of FIG. 2B, the steam turbine 102 doesnot have a coast down time of several minutes, as in FIG. 2A, butinstead may take seconds or noticeably less time. Accordingly, thedeceleration line 208 (indicative of shaft 114 rotation speed) in apotential reverse rotation event is much faster (e.g., 2-5 times faster)than the typical shutdown line 204 (e.g., up to 30 minutes). Thereversing point 210 reflects the moment the rotor 112 stops rotating inits designed direction and begins rotating in the reverse direction (asmeasured by the shaft 114 rotating in a reverse direction). The camelhump line 212 reflects when the steam turbine system 100 increases speedrunning in the reverse direction. The camel hump may reach a max speedin the reverse direction as shown at point 214. The reverse rotationsmay then begin to slow, as reflected in line 216, to a stop as any backpressure causing the reverse rotation abates.

The camel hump pattern, as illustrated in FIG. 2B, includes multiplespeed increases (e.g., line 212) and decreases (e.g., deceleration line208 and line 216) different from that described in a normal shutdown.The monitoring system 126 may, for instance, receive data from thesensors 120 that the processor 128 determines to be representative ofspeed changes similar to a speed decrease of the deceleration line 208,the speed increase of line 212, and the speed decrease similar to line216. The processor 128 may then determine an initial value (e.g.,zero/one) by comparing the received data representative of the camelhump pattern to the normal operating pattern described above. If theprocessor 128 determines that the camel hump pattern has occurred, theinitial value may be set to one to indicate true. The processor 128 maythen weight (e.g., a percent value) the initial value based on howaccurate the camel hump pattern reflects a reverse rotation event. Forinstance, the camel hump pattern is highly consistent with reverserotation events. Accordingly, a heavy weight (e.g., 70-95% consistencywith reverse rotation) may be combined with the initial value to form aweighted value. The weighted values may then be combined to determinewhether a reverse rotation has occurred. As discussed below, anotherembodiment of detecting the reverse rotation, as represented in FIG. 2B,may include comparing the rate of change of speed to the normaloperating rate of change of speed or comparing the shut down time (e.g.,the coast down time) to a normal operating shut down time.

FIG. 2C is another speed trend plot 202 during a reverse rotation eventof the steam turbine system 100. This may occur, for example, when anidentical sister machine (e.g. with a common discharge header 118) isproviding constant back pressure and continues to force the steamturbine 100 to rotate in reverse until the matter is noticed (e.g., by auser) and corrections are made, for example, to valves in the processline to eliminate the reverse rotation energy source. As mentionedabove, it is important to bear in mind that the steam turbine 100 isused merely as an example, and the underlying principle is that thedriven piece of equipment becomes the driver. At the first line 218, therotor 112 of the steam turbine 102 may be running at its operating RPM.When the steam turbine system 100 shuts off, the speed of the rotor 112decreases rapidly (e.g. 4-10 times faster than normal) until it reachesthe reversing point 210 (e.g., zero speed). The rotor 112 then rapidlyaccelerates (e.g. in under 30 seconds) in the reverse direction, and thereverse speed line 220 reflects that the reverse rotation may even befaster (in terms of magnitude i.e. rpm value) than the operational RPMand may exceed design limits. For instance, the steam turbine 102 may bedesigned to run at an operating speed of 13,000 rpm shown at line 218.The steam turbine 102 may reverse and go beyond (e.g. 15,000 rpm) theoperating speed as indicated by the data plotted on reverse speed line220. Accordingly, an over speed condition reached through such pattern(hereafter referred to as “rift valley”) suggests that a reverserotation event has occurred.

In order to detect the over speed condition, as illustrated in FIG. 2C,the processor 128 may determine an initial value by comparing the speeddata to normal operating patterns. The normal operating patterns couldreflect, for instance, the designed operational RPM of the steam turbinesystem 100. For instance, if the speed data is greater than the designedoperational RPM, the initial value may be one (e.g., true). Theprocessor 128 may then determine a weighted value based on the initialvalue and a weight. The weight may be, for instance, predetermined basedon how accurate the over speed rift valley condition reflects a reverserotation event. The weighted value can then be combined with otherweighted values, such as the camel hump weighted value described above.The combined value allows the processor 128 to determine whether areverse rotation has occurred.

As previously noted, an additional comparison may be made based on theshortened coast down time described above. The coast down time of thesteam turbine 102, as illustrated in FIGS. 2B and 2C, is drasticallyreduced prior to the occurrence of a reverse rotation event. Thus, theprocessor 128 may calculate the slope that the rpm changes with respectto time. If the speed of the rotor 112 is decreasing at a rate fasterthan normal operating patterns, it suggests that a reverse rotationevent is imminent. Accordingly, the processor 128 will determine that areverse rotation event has occurred and assign an initial value (e.g.,one/zero) indicating as such. Similarly, if the time between two pointsduring shutdown events suggests a faster decay compared to normaloperating patterns, the processor 128 can assign an initial valueindicating that the decay was different from normal operating patterns.Similar to above, these initial values can be weighted and combined asthe processor 128 determines whether a reverse rotation has occurred. Inaddition to speed data received from the sensors 120, vibration data maybe used to determine the occurrence of a reverse rotation event. One wayof visually analyzing vibration data is with an orbit plot.

Orbit plots show the vibration precession as the shaft 114 rotates asmonitored by the sensors 120. As described above, the processor 126 maysimply analyze the vibration and speed data to determine that a reverserotation will occur, is in the process of occurring, or has alreadyoccurred, and generate a signal 136 indicating as such. In thealternative, the processor 128 may output data similar to FIGS. 3A and3B to a display 302 or a generated report as further evidence(confidence) of a reverse rotation event.

FIG. 3A is a filtered 1X orbit plot 300 illustrating an embodiment ofthe data received by the monitoring system 126 during normal operationof a rotating machine meant to operate in the counter clockwisedirection. A display 302 may be an internal display 134 or it may be aremote display 302 on a workstation on the network. Bear in mind, FIGS.3A and 3B have a display 302 for illustrative purposes, however, themonitoring system 126 may determine vibration precession internally(e.g., hardware) with signal processing using the processor 128 and donot necessarily need a display 302. The display 302 has a vertical Yaxis 304 and a horizontal X axis 306 which is representative of datareceived from the sensors 120 on the shaft 114 in the Y direction and Xdirection of the three dimensional coordinate system 124 respectively.Note that the horizontal X axis is approximately (e.g., less than 20degrees different from) 90 degrees clockwise of the Y axis. The plot 300is filtered at one times the shaft 114 rotational speed to compensatefor problems with the shaft 114 surface, such as scratches. The orbitplot 300 tracks the precession of vibration with a line 308. Thedirection of normal rotation 311 is shown in the top left to be counterclockwise. In general, the direction of precession of most vibrationsignals follow the direction of rotation. For instance, a shaft 114designed to rotate in the counter clockwise direction would mostcommonly have vibration signals in the counter clockwise direction. FIG.3A illustrates forward precession of vibration in the counter clockwisedirection of such a shaft 114 as indicated by an arrow 310.

FIG. 3B is a similar plot 300 illustrating precession of vibration inthe opposite direction (e.g., reverse rotation) of the designed shaft114 rotation. FIG. 3B shows a line 312 going in the opposite directionof the line 308 in FIG. 3A as further indicated by an arrow 314. Thedirection of normal rotation 316 is still in the counter clockwisedirection, however, the precession of vibration is indicated by thearrow 314 to be in the clockwise direction. This reverse precession ofvibration from the normally forward precession is highly indicative of areverse rotation event when coupled with the existence of the “camelhump” or “rift valley” speed trend patterns. The rotor is actuallyvibrating in the forward precession (vibration precession same asrotating direction) since the vibration is actually in the samedirection of rotation, but the rotation is reverse from the normalrotation direction. Thus, it is described as a reverse precession ofvibration. Additionally, reverse rotation sometimes causes rubbing inthe bearings or seals as the shaft 114 moves to an abnormal positionwhen the rotor 114 crosses the zero speed. The zero speed is the pointat which the rotor 112 stops moving forward and begins to rotate in thereverse direction. The rubbing may produce harmonics and sub harmonics.

The orbit plots 300, as illustrated in FIGS. 3A and 3B, are indicativeof vibration data received by the monitoring system 126 from the sensors120. Similar to the speed data, the processor 128 may compare thevibration data received from the sensors 120 with normal operatingpatterns. As described above, the comparisons may, for example, bewritten in code and stored in the memory 130. The normal operatingpatterns and vibration data may be a representation of the phaserelationship between the X sensor and the Y sensor. For instance, thephase relationship may establish an initial condition corresponding tothe X sensor leading the Y sensor in phase by approximately 90 degrees.If rotation reverses, the phase relationship may correspond to the Ysensor leading the X sensor in phase by approximately 90 degrees. Thecomparison of the normal operating patterns and the vibration data mayresult in an initial value (e.g. zero/one). The initial value may beassigned a weight based on how accurate the reverse precession ofvibration data reflects a reverse rotation event. The weighted value canthen be combined with other weighted values, such as the speed weightedvalues described above. If the combined value is above a presetthreshold value (e.g., the probability and severity of a reverserotation occurrence is above the preset threshold value), the processor128 may have determined that a reverse rotation has occurred.

As will be appreciated, data used to generate the speed trend plot ofFIGS. 2A, 2B, and 2C and/or the orbit plot of FIGS. 3A and 3B are notthe only means of displaying speed and vibration data. For example, dataused to generate a spectrum waterfall plot may also be used to displaythe reversal of 1X positive (forward precession) and negative (reverseprecession) components.

Turning now to FIG. 4, a flow diagram is presented, illustrating anembodiment of a process useful in a rotor reverse rotation eventmonitoring system 126. The process 400 may include code or instructionsstored in a non-transitory computer-readable medium (e.g., the memory130) and executed, for example, by the one or more processors 128included in the reverse rotation monitoring system 126. The process 400may begin with a validation (block 401) that the sensors 120 areproperly configured. The validation (block 401) may include, forinstance, the processor 128 validating that the sensors 120 are wiredcorrectly and all the vibration signals are reporting forward precessionvibration. The validation (block 401) establishes an initial conditionvalidating that all is properly configured. If the sensors areimproperly configured (e.g., X & Y sensors wired incorrectly as Y&X),false reverse rotation detection may occur. Next, the processor 128 mayreceive (block 402) speed and vibration signals from the sensors 120.The speed signals may indicate that the steam turbine system 100 speedis increasing, decreasing, constant, or stopped. The vibration signalsmay indicate a precession of vibration, harmonics, and sub harmonics ofthe steam turbine system 100. The speed and vibration signals may beused to determine that the steam turbine system 100 is shutting down. Inthe alternative, an indication that the steam turbine system 100 isshutting down may be received on the inputs and outputs of thecommunication interface 132 from the sensors 120, the turbine 112, theshaft 114, or from wired or wireless transmission on the network.

The process 400 may then continue with the processor 128 determining(block 404) that a reverse rotation event will likely occur or hasoccurred based on the speed and vibration data. That is, thedetermination of an occurrence of reverse rotation may include adetermination of the likelihood of a future occurrence of a reverserotation event and/or the recognition of a reverse rotation event havingoccurred. This determination includes any combination of, for instance,the three speed comparisons and the two vibration comparisons describedabove. Each of the comparisons result in an initial value. The initialvalues are given weights (e.g., weighted multipliers) resulting in aweighted value. The weights may be based on the severity and confidencethat a reverse rotation has occurred. For instance, the weights may beabove (e.g., 1.5, 2, or 3) a medium value (e.g., one) if the comparisonsreflect a strong correlation to reverse rotation events. The weights maybe below the medium value (e.g., 0.5 or 0.75) if the comparisons have aweak correlation to reverse rotation events. The weighted values arecombined to reflect the likelihood that a reverse rotation event hasoccurred. If this combined value (e.g., likelihood) is above a presetthreshold value, the processor 128 determines that a reverse rotationevent has occurred, and a signal 136 is generated (block 406) indicatingthat a reverse rotation has occurred.

Technical effects of the present application include providing an alertsignal and displaying data to a user. Additionally, interaction with amonitoring system may allow for user interaction to adjust the weights,normal operating patterns, and threshold for detecting reverse rotation.In this manner, precise settings for an individual rotating machine maybe accomplished. In this way, the monitoring system may be able to alerta plant, a user, or a workstation of the reverse rotation. This mayallow for greater protection and/or proactive diagnostics for a rotatingmachine, thus improving the life span and usefulness of such equipment.

This written description uses examples to disclose the invention,including the best mode, and also to enable any person skilled in theart to practice the invention, including making and using any devices orsystems and performing any incorporated methods. The patentable scope ofthe invention is defined by the claims, and may include other examplesthat occur to those skilled in the art. Such other examples are intendedto be within the scope of the claims if they have structural elementsthat do not differ from the literal language of the claims, or if theyinclude equivalent structural elements with insubstantial differencesfrom the literal languages of the claims.

The invention claimed is:
 1. A device, comprising: a display; acommunication interface configured to receive a signal related to arotational speed, a vibration, or any combination thereof of a rotatingmachine element from each of a plurality of sensors coupled to therotating machine element, wherein the plurality of sensors include afirst sensor and a second sensor positioned orthogonally with respect toone another; a memory for storing an operating pattern of the rotatingmachine element, wherein the operating pattern is related to thereceived signal; and a processor coupled to the display, thecommunication interface and the memory, wherein the processor isconfigured to: determine an initial operating condition of the pluralityof sensors; determine an occurrence of reverse rotation of the rotatingmachine element by comparing the signal received from the communicationinterface to the operating pattern stored in the memory; generate areverse rotation event signal indicative of the occurrence of thereverse rotation of the rotating machine element; and provide thereverse rotation event signal via the display.
 2. The device of claim 1,wherein determining the initial operating condition of the plurality ofsensors includes validating that at least two sensors of the pluralityof sensors are configured to generate a signal indicative of a forwardprecession vibration of the rotating machine element.
 3. The device ofclaim 1, wherein the generated reverse rotation event signal includes analert and reverse rotation event data.
 4. The device of claim 3, whereinthe reverse rotation event data includes at least one of a speed trenddata representation, an orbit data representation, and a cascade datarepresentation.
 5. The device of claim 1, wherein the processor isconfigured to assign an initial value associated with the determinedoccurrence of reverse rotation, wherein the initial value indicates adifference between the operating pattern stored in the memory and thereceived signal.
 6. The device of claim 1, wherein the memory isconfigured to store the operating pattern as related to a coast downtime, a rate of speed increase or speed decrease, an operational speed,or any combination thereof of the rotating machine element.
 7. Thedevice of claim 1, wherein the processor is further configured toprovide the reverse rotation event signal in a generated report.
 8. Asystem, comprising: a plurality of sensors configured to monitorrotating machinery, each of the plurality of sensors configured togenerate a signal based on a physical characteristic of the rotatingmachinery, wherein the plurality of sensors include a first sensor and asecond sensor positioned orthogonally with respect to one another; and amonitoring system comprising a processor, a memory, and a display, themonitoring system configured to: receive the signal; determine aninitial operating condition of the plurality of sensors; determine anoccurrence of reverse rotation of the rotating machinery by comparingthe signal to an operating pattern of the rotating machinery to generatean initial value; generate a reverse rotation event signal indicative ofthe occurrence of a reverse rotation of the rotating machinery; andprovide the reverse rotation event signal.
 9. The system of claim 8,wherein the processor is configured to assign an initial valueassociated with the determined occurrence of reverse rotation, whereinthe initial value indicated a difference between an operating patternstored in the memory and the received signal.
 10. The system of claim 9,wherein the processor is configured to determine the occurrence ofreverse rotation of the rotating machinery by applying predeterminedweighting values to the initial value to generate a combined valuedetermine the occurrence of reverse rotation of the rotating machineryby comparing the combined value to a preset threshold.
 11. The system ofclaim 10, wherein the processor is configured to determine theoccurrence of reverse rotation of the rotating machinery by comparingthe combined value to a preset threshold.
 12. The system of claim 8,wherein the processor is configured to determine the occurrence ofreverse rotation of the rotating machinery by comparing a phaserelationship between a first signal of a first sensor and a secondsignal of a second sensor to an initial condition, wherein the initialcondition comprises the first signal leading the second signal, andwherein the occurrence of reverse rotation comprises the second signalleading the first signal in phase.
 13. The system of claim 8, whereinthe plurality of sensors are configured to generate a signal based on arotational speed or a vibration of the rotating machinery.
 14. Thesystem of claim 8, wherein the monitoring system is further configuredto determine that the rotating machinery is shutting down based on thesignal.
 15. The system of claim 8, wherein the processor is configuredto determine the initial operating condition of the plurality of sensorsbased on validating that at least two sensors of the plurality ofsensors are configured to generate a signal indicative of a falsereverse rotation of the rotating machinery.
 16. The system of claim 8,wherein the generated reverse rotation event signal includes an alertand reverse rotation event data.
 17. The system of claim 8, wherein thereverse rotation event data includes at least one of a speed trend datarepresentation, an orbit data representation, and a cascade datarepresentation.
 18. The system of claim 8, wherein the processor isconfigured to assign an initial value associated with the determinedoccurrence of reverse rotation, wherein the initial value indicates adifference between the operating pattern stored in the memory and thereceived signal, wherein the operating pattern stored in the memoryrepresents an expected operating pattern of the rotating machinery. 19.The system of claim 8, wherein the memory is configured to store theoperating pattern as an expected operating pattern associated with acoast down time, a rate of speed increase or speed decrease, anoperational speed, or any combination thereof of the rotating machinery.20. The system of claim 8, wherein the reverse rotation event signal isprovided via the display of the monitoring system.
 21. The system ofclaim 8, wherein the reverse rotation is provided in a report generatedby the monitoring system.
 22. The system of claim 8, wherein themonitoring system is further configured to provide the reverse rotationevent signal as an alert to a remote workstation coupled to themonitoring system and/or for display at the remote workstation.